Frankly, I think the police should be either commended or chastized (can't decide) for not pounding the little piece of vomit into paste.
At least he's 18 and there will be some pathetic attempt at justice. (as opposed to under 18 wrist slap)

Not only should he be severely punished and perhaps committed, his parents need to be investigated. You don't get that twisted by that age on your own.